I chose this pedal as I love that classic Muff sound, but there are extras on this pedal for those who want a couple of different options in one pedal. Purists might not like the added features, but personally I see nothing wrong with having more options to choose from.
The "extra additions" on this pedal are the two micro-toggles, labelled "Tone" and "Wicker" respectively.
The "Tone" switch allows you to have the full, original Muff tone circuit in the On position, or bypass the tone circuit in the Off position. This switch radically changes the sound of the pedal, and you can use it to really shape the kind of fuzz you can get out of it. In my experience, switching the tone toggle to the Off position gives me a gnarlier, crunchier Fuzz. In the On position, you get that smoother, more original Big Muff sound.
*WARNING* One thing I wasn't completely prepared for when experimenting with the Tone switch the first time I plugged this pedal in, you may want to turn your amp volume down. I had the pedal's volume quite high when playing with the tone switch in the On position, but when I flicked it to the Off position, it seemed as thought I had let the beast off the leash. It absolutely ROARED at me, it was so raucous and untamed that had it been a wild animal, it would have torn my face off. So naturally I loved it! :)
The "Wicker" switch is quite a nice addition, it seems to keep some of the higher frequencies when you turn down the sustain knob, whereas if you turned the Wicker switch off and rolled back the sustain, you would lose some highs and get a muddier sound, as you would with the original Muff. It's a nice little switch that just adds a little more flexibility when shaping your ideal tone.
In conclusion, I would say that even if you were an original Big Muff purist, this pedal is worth looking into, especially if pedal board space is an issue and you do want more tone options in your signal chain. After all, you're pretty much getting the original Muff sound but with a few extras for those times when you just want to experiment... or maybe you will find something in the extra features that you actually prefer over the original. It's worth a go!